title: Autosomal male determination in a spinosad-resistant housefly strain from Denmark.
abstract: BACKGROUND
  The housefly, Musca domestica L., is a global pest and has developed resistance to most insecticides applied for its control. The insecticide spinosad plays an important role in housefly control. Females of the Danish housefly strain 791spin are threefold more resistant to spinosad than males in this strain. The factor responsible for spinosad resistance in the strain is unknown, but previous studies suggest a role of cytochrome P450s for detoxification of spinosad. Sex determination in the housefly is controlled by a male-determining factor (M), either located on the Y chromosome or on one of the five autosomes (I to V).
  
  
  RESULTS
  The authors performed a series of crosses and backcrosses, starting with cross of 791spin and the susceptible reference strain aabys (bearing morphological mutations on each autosome). These flies were evaluated for gender and bioassayed to determine levels of resistance to spinosad. Sex determination in 791spin is due to a male factor on autosome 3.
  
  
  CONCLUSIONS
  The most likely explanation for the differentiation of spinosad resistance between males and females is a recessive spinosad resistance factor on autosome III.
authors.affiliation: Department of Agroecology, Aarhus University, Denmark; Department of Entomology, Cornell University, USA.
authors.forename: Dorte H
authors.initials: DH
authors.lastname: Højland
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Scott
authors.forename: Karl-Martin
authors.initials: KM
authors.lastname: Vagn Jensen
authors.forename: Michael
authors.initials: M
authors.lastname: Kristensen
mesh_terms: D000818:Animals; D003718:Denmark; D004338:Drug Combinations; D005260:Female; D008040:Genetic Linkage; D006793:Houseflies / Q000187:drug effects* / Q000235:genetics*; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D018942:Macrolides / Q000494:pharmacology*; D008297:Male; D019849:Sex Determination Processes
chemical_list: D004338:Drug Combinations; D007306:Insecticides; D018942:Macrolides; C415329:spinosad
keywords: Musca domestica; autosomal sex determination; insecticide resistance